Expansible well scraper



July 31, 1956 v. EMANUEL ETAL 2,756,968

EXPANSIBLE WELL SCRAPER Filed April 12, 1954 y?, la J7?, g, 20 236 $5JNVENToRs. VvcE/vr EMA/vue., Vies/z. l?. DOUGLAS, By

Arroz/vay- 2,756,968' nxPANsiLE WELL SCRAPER' Vincent Emanuel, Arcadia,and Virgil R. Douglas, Lynwoo'd, Calif., assignors to Grant Oil ToolCompany, Los Angeles, Calif., a corporation of California ApplicationApril 12, 1954, seriaiNo. 422,398

'1o claims. (c1. 25a-76) nited States Pat the present invention,pivotally mounted for swinging movement within radial slots in the bodyand actuated in their swinging movement by and in response to axialmovement of a mandril in the body. s

The invention may be further characterized as relating to a form of wallscraper in which the mandril is actuated during its movement in onedirection by the pressure of circulating iiuid being conducted throughthe body, and actuation of the cutters occurs by virtue of anessentially geared relation between the mandril and inner end portionsof the cutters. Illustrations of this general type of wall scraperappear in the Johnson Patents No. 2,049,450, issued August 4, 1936, andNo. 2,116,898, issued May 10, 1938. The prior practice, as exemplifiedby these patents, has been to position the cutters in radial axialplanes of the body and mandril and to locate the interengaging cutterand mandril actuating projections or teeth in the same planes, or tooffset the cutter planes from the radial axial planes of the body andmandril, with the actuatingprojections or teeth also olfset. (As hereinused, the term axial radial plane, means a plane intersecting both thelongitudinal center line or axis of the body and mandril, and a radialline intersecting thataxis.) Experience has shown that when positionedin such radial axial planes, little mechanical advantage is availablennless the actuating teeth are extended into the wash pipe in which caseuid erosion shortens the life of the teeth. With an offset actuatingtooth arrangement, the actuating teeth are extended past the axis of thebody, thereby increasing the mechanical advantage, the teeth are not'exposed to detrimental fluid erosion, and the uid is conducted past theteeth to the bottom of lthe tool where it can clean and lubricate thepilot bit. The invention has for one of its major objects to provide formounting of the cutters in radial axial planes of the body, whilepositioning the actuating teeth in a rack and pinion relation atlocations offset from such planes and in a manner such that the teethmay be positioned and extended laterally of the mandril at its sideswithout being subject to any limitations otherwise imposed by thecomparatively ,y 2,756,968 Patented yJuly 31, 1956 circulation throughthel body and mandril, and under coni ditions s'uchithat the lluidypressure actuates the mandril throughoutoneof its strokes. As to thisfeature, the invention is'concerned with the minimizing of 4abrasivewear of the mandril as a result of the iluid ilow velocity and the.presence of Vanyl abrasive particles in the uid. In Icontemplation ofminimizing. Huid abrasion ofy the mandril, the latter is/pr'ovided witha hollow fluid control head containing'apertures through which thecircul'ationfluid enters in separate streams which impinge withintheihead and` thereby so dissipate their energy as to Vprevent thecontinuance'ofvelocity effects which otherwi'se would produce'wear."(Ivt may be mentioned that mixingheads, as such, are known from suchprior art as the Grant Patent' 2,072,859, and Santiago Patent2,284,170.) Inthevpresentgtool'the iluid leaving the control head isvconducted in a course of How straight through" the bore ofthe mandril(in distinction tok llow outside the mandril) 'so as to further minimizethe ex# istance of any high velocity lor other ow conditions that mightresult in seriouswear of the parts as well as Vto provide iiuidcirculation through to the bottom of the tool. The inventionhasuv'arious radditional features and objects, all of' ,whichl will beapparent from the following detailed description ofV an illustrativeembodiment of the invention showirby` the accompanyingdrawing, in whichEig. ljisa vview'y showing the tool in longitudinal sec"- tionwith thecuttersV in 'expanded position;

Fig. 2 is a fragmentaryV sectional enlargement showing oneof the cuttersin contracted position; and f f Figsy and 4 areenlarged cross-sectionstaken respectively on` lines 3v-3and 4-4 of Fig. 1V. 4 Referring rstto'thegeneral showing of Fig. 1, the tool comprises a tubular body 10into the upper threaded box end 11"l of which may be screwed a serviceor tool joint V12 for connection vwith the drill string 13. The lowerend 'of the bodyvltl may be connected to or formed integrally withany'appropriate tool such as the bit 14 which may for example be a pilotbit having a diameter less than that of ar pre-existing well hole 110,the bit being usable to remove'obstructions, cave-inv material andthelike' in 'theholeL As the drawing'illustrates, ythe body is formed witha succession of counterbor'es' 15, 16, 17, and 18, the lattercommunicating withv passage '19 through which circulating lluid isdischarged from the narrow radial spacing between the cutters andmandril. l

Further contemplated is an arrangement of, the cutter and mandril teethsuch that the cutters are positively actuated by the mandrildisplacement throughout the envtire swinging range of the cutters, allin a manner involving the use of a pair of teeth on each cutter whichare successively engageable by and between three spaced shoulders orprojections on the mandril so that there is continuous and progressivedriving engagement of the mandril against the cutters.

The present tool embodies certain other features and improvements havingto do with the maintenance of uid drill string through ,the tool to therbit. The body 10 contains Va tubular mandril assembly, generallyindicated at 20, which may be described as comprising a body portion 21carrying at its lower end a wash pipe 22 extending within the body bore18. Downward displacement ofthe mandril is resisted by a coil spring 23confined between the body shoulder 24 and the mandril headk 25.'` Thelatter, working in bore 15, may carry anyJ appropriate type and form ofpacking 26 to serve as a fluid-tight plunger against which circulatingfluid introduced from the drill string into the body bore 15, operatesto displace the plunger downwardly against the resistance of spring23.The function of the spring is 'to keep the cutter members 33 illustratedas blades pivotally mounted to the body 10'in the collapsed posi# tionduring transport and prior to scraping. The blades are closed primaiilyby positive contact with the formation when the tool is raisedvertically in the hole.v -This action forces the mandril to itsuppermost positiony and the spring tends tol keep it there untilsuicient tluid presi sure is exerted to re-open the blades. Themandrilcarries a circulation control head, gen erally indicated at 27,`which comprises a lower tubular section 28 threaded into the mandril,and an upper 'sec` tion 29, the top 30 of which is essentiallyhemispherical in shape andcontains a pluralityy of openings 31 throughwhich the circulating fluid flows from the body bore in separate streamsinto the mandril channel 32. Entering through the openings 31, the fluidstreams merge and dissipate. their velocity energy, the uid thenceassuming a straight course. of flow down through the mandril bore orchannel, and wash pipe 22.

The body is shown typically to carry three cutters 33 which, as shown inFigs. 3 and 4, lie in radial axial planes P of the body, with thecutting sides or edges 33a o f the cutters offset from but substantiallyparallel to these planes. The blades are accommodated within the radialbody slots 34 and are retained by pins` 35, for radial swinging movementbetween the Fig. 1 and Fig. 2 positions. At their inner angularlyextending end portions 33b, the cutters carry a pair of spaced lugs orteeth 36 `which are offset from the plane P and extend along and inoverlaping relation with the side of the mandril. Thus we have thebodies of the cutters 33 lying directly in the planes P with relativelynarrow radial spacing at 38 from the mandril, while the teeth 36 areoffset to the side of the mandril where they may be given suchdimensions and extents for best structural and functional purposeswithout any limitations that would otherwise result from confinementwithin the narrow clearance at 38.

The portion 136 of the mandril 20 alongside which the toothed blade ends33b extend in overlapping relation has an essentially triangular crosssectional shape forming outer sides or ats 236 extending longitudinallyof the mandril between adjacent blades. The flats 236 preferably lieparallel to and adjacent the inner faces 133 of the three blade ends.33h respectively in order to resist relative rotation between themandril and blades about the mandril axis. j

The planes of the mandril flats 236 are offset from and extend generallyparallel to the planes P so that as the cutter blades pivot about pins35 their inner faces 133 sweep alongside the mandril flats 236.

The triangular portion 136 of the mandril also has three sets oflongitudinally spaced projections 40, 41 and 42. preferably formedintegrally with the mandril to extend outward from the at sides 236thereof. The sets of projections 40, 41 and 42 are formed alike insection or plan as exemplified by the showing in Fig. 3 of the threeprojections 40 extending outwardly respectively from the three flatmandril sides 236. Each of the. pro.- jections 40, 41 and 42 has avertical planar surface 13S (see upper projection in Fig. 4) received incloselyy spaced relation to a cylindrically extending surface 23.8 on anassociated cutter blade 33, and has a smaller relatively angularvertical planar surface 139 in closely spaced relation to a frustoconical surface 239 on the cutter. Also, each projection has an outervertical arcuate surface 338 engageablewith bore 17, and has an inwardlyextending vertical surface 339, Spaces 43 and 44 are formed betweenprojections 40 and 41 and between projections 41 and 42 respectively forreceiving the spaced teeth 36 of the cutter blades which interfit withinthe spaces 43 and 44 when the teeth are engaged bythe projections 40 and41 on downward displacement of the mandril.

In considering the operation of the cutters, assume the parts first tobe in the Fig. 2 position with the cutters fully contracted by virtue ofthe spring urged upward thrust of the mandril projection 42 against thelower cutter tooth 36. As fluid pressure is applied to its plunger head,the mandril is displaced downwardly, first causing the mandrilprojection 41 to engage the top surface of the lower cutter tooth 36 andinitiate outward swinging movement of the cutter. As the mandrilcontinues its downward movement, the upper cutter tooth 36 is swunginwardly to a position at which it is engageable by the upper mandrilprojection 40, enabling the latter to continue the exertion of expandingthrust against the cutter until just before the latter reaches its fullyexpanded condition of engagement with the body shoulder 45, as

shown in Fig. l. At the limit of the cutter movement as determined byshoulder 45, mandril projections 40 and blade teeth 36 are spaced aparta short distance at 145, to prevent vibration and wear of the mandriland associated parts as a result of vibration of the blades in use. Inorder to allow for such spacing of projections 40 and the blade teeth,the downward movement of the mandril is limited at the position shown inFig. l by engagement of shoulders on the mandril and body at 125. Uponrelease of the fluid pressure, the spring 23 causes the mandril to swingthe cutters by a reverse sequence of engagement between the mandrilprojections and cutter teeth, until the cutters are restored to the Fig.2 contracted position.

We claim:

l. An improved oil well tool comprising a tubular body, a plurality ofcutter blades pivotally mounted in slots in the body for radial swingingmovement, a mandril movable axially within the body, said mandril havinga plurality of outer flats extending between adjacent cutter blades,each of said cutter blades lying in an axial radial plane of the bodyand mandril and having an inner toothed end portion offset from saidplane and extending alongside one of said flats, and projections on themandril engageable with said end portions of the cutter blades to swingthe cutter blades upon axial movement of the mandril.

2. An improved oil well tool comprising a tubular body, a plurality ofcutter blades pivotally mounted in slots in the body for radial swingingmovement, a mandril movable axially within the body, said mandril havinga polygonal cross section portion forming a plurality of outer atsextending between the cutter blades, each of said cutter blades lying inan axial radial plane of the body and mandril and having an innertoothed end portion offset from said plane and extending alongside oneof said flats, and projections on the polygonal cross section portion ofthe mandril engageable with said end portions of the cutter blades toswing the cutter blades upon axial movement .of the mandril.

3. An improved oil well tool comprising a tubular body, three cutterblades pivotally mounted in slots in the body for` radial swingingmovement, a mandril movable axially within the body, said mandril havinga substantially triangular cross section portion forming outer flatsextending between the cutter blades, each of said cutter blades lying inan axial radial plane of the body and mandril and having an innertoothed end portion offset from said plane and extending alongside oneof said flats, and projections on the substantially triangular crosssection portion of the mandril engageable with said end portions of thecutter blades to swing the cutter blades upon axial movement of themandril.

4. An improved oil well tool comprising a tubular body, a plurality ofcutter blades pivotally mounted in slots in the body for radial swingingmovement, a mandril movable axially within the body, said mandril havinga plurality of outer ats extending between adjacent cutter blades, eachof said cutter blades lying in an axial radial plane of the body andmandril and having an inner end portion offset from said plane andcarrying a pair of spaced teeth adjacent the mandril and extendingalongside one of said flats, and means forming on the mandril aplurality of spaced shoulders receiving said teeth between them andprogressively engageable with the teeth to swing the cutter bladesinwardly and outwardly of the body upon axial movement of the mandril.

5. An improved oil well tool comprising a tubular body, a plurality ofcutter blades pivotally mounted in slots in the body for radial swingingmovement, a mandril movable axially within the body, said mandril havinga substantially triangular cross section portion forming outer atsextending between the cutter blades, each of said cutter blades lying inan axial radial plane of the body and mandril and having an inner endportion offset from said plane and carrying a pair of spaced teethadjacent the mandril and extending alongside one of said ats, and meansforming on the substantially triangular cross section portion of themandril a plurality of spaced shoulders receiving said teeth betweenthem and progressively engageable with the teeth to swing the cutterAblades inwardly and outwardly of the body upon axial movement of themandril.

6. An improved oil well tool comprising a tubular body, a plurality ofcutter blades pivotally mounted in slots in the body for radial swingingmovement, a mandril movable axially within the body, said mandril havinga plurality of cuter flats extending between adjacent cutter blades,each of said cutter blades lying inan axial radial plane ofthe body andmandril and having an inner toothed end portion odset from said planeand extending alongside one of said ats, and projections on the mandrilengageable with said end portions of the cutter blades to swing thecutter blades upon axial movement of the mandril, each ot' said cutterblades having an outer cutting edge lying in the plane of its said innertoothed end portion.

7. An improved oil well tool comprising a tubular body, a plurality ofcutter blades pivotally mounted in slots in the body for radial swingingmovement, a mandril movable axially within the body, said mandril havinga plurality of outer flats extending between adjacent cutter blades,each of said cutter blades lying in an axial radial plane of the bodyand mandril and having an inner end portion oiset from said plane andcarrying a pair of spaced teeth adjacent the mandril and extendingalongside one of said flats, and means forming on the mandril aplurality of spaced shoulders receiving said teeth between them andprogressively engageable with the teeth to swing the cutter bladesinwardly and outwardly of the body upon axial movement of the mandril,each of said cutter blades having an outer cutting edge lying in theplane of its said teeth.

8. An improved oil well tool comprising a tubular body, a plurality ofcutter blades pivotally mounted in slots in the body for radial swingingmovement, a mandril movable axially within the body, said mandril havinga plurality of outer flats extending between adjacent cutter blades,each of said cutter blades lying in an axial radial plane of the bodyand mandril and having an inner toothed end portion offset from saidplane and extending alongside one of said ats, and projections on themandril flats engageable with said end portions of the cutter blades toswing the cutter blades upon axial movement of the mandril, and meansfor axially displacing the mandril in one ldirection by the pressure offluid exertible against said means, said means allowing uid passagethrough an imperforate -axial bore in the mandril at the inside of saidcutter blades.

9. An improved oil well tool comprising a tubular body,

` a plurality of cutter blades pivotally mounted in slots in the bodyfor radial swinging movement, a mandril movabley axially within thebody, said mandril having a pluv pressure of iluid exertible againstsaid means, said means allowing fluid passage through an imperforateaxial bore in the mandril at the inside of said cutter blades.

10. An improved oil well tool comprising a tubular body, a plurality ofcutter units pivotally mounted in slots in the body for radially outwardswinging movement and each swinging in essentially an axial radial planeof the body, a mandril movable axially within the body and having -aplurality of outer flats extending between adjacent cutter units, eachof said cutter units having an inner toothed end portion oiset from saidplane and extending alongside one of said flats, and projections on themandril engageable with said end portions of the cutter units t0 swingthe cutter units upon axial movement of the mandril.

References Cited in the le of this patent UNITED STATES PATENTS1,478,306 Sweetman Dec. 18, 1923 1,981,262 Burt Nov. 20, 1934 2,049,450Johnson Aug. 4, 1936 2,072,859 Grant Mar. 9, 1937 2,116,898 Johnson May10, 1938 2,238,998 Grant Apr. 22, 1941 2,284,170 Santiago May 26, 1942

1. AN IMPROVED OIL WELL TOOL COMPRISING A TUBULAR BODY, A PLURALITY OFCUTTER BLADES PIVOTALLY MOUNTED IN SLOTS IN THE BODY FOR RADIAL SWINGINGMOVEMENT, A MANDRIL MOVABLE AXIALLY WITHIN THE BODY, SAID MANDRIL HAVINGA PLURALITY OF OUTER FLATS EXTENDING BETWEEN ADJACENT CUTTER BALDES,EACH OF SAID CUTTER BLADES LYING IN AN AXIAL RADIAL PLANE OF THE BODYAND MANDRIL AND HAVING AN INNER TOOTHED END PORTION OFFSET FROM SAIDPLANE AND EXTENDING ALONGSIDE ONE OF SIAD FLATS, AND PROJECTIONS ON THEMANDRIL ENGAGEABLE WITH SAID END PORTIONS OF THE CUTTER BLADES TO SWINGTHE CUTTER BLADES UPON AXIAL MOVEMENT OF THE MANDRIL.